Trip jack



Aug. 28, 1923.

F. H. SCHWERIN TRIP JACK 4 Shets-Sheec 1 Filed May 12, 1922 A TTORIVEP Aug. 28, 1923. 1,466,195

- F. H. SCHWERIN May 12, 1922- 4 Sheets-Sheet 2 Ill ' Arm/mu I INVENTOR Aug. 28, i923. v I F. H. SCHWERIN Filed May '12 1922 Arm/my Patented Aug. 28, 1923.

* rrso STATES A Me ea PATa'reriee.

FRANK II. SCHWERIN, OF WEST VIEW, PENNSYLVANIA, A SSIGNOR TO THE DUFF MANUFACTURING COMPANY, or PENNSYLVANIA.

Application filed May 12,

To all whom it may, concern.

Be it known that I, FRANK H. SCHWERIN,

' a citizen of the United States,and a resident.

of the borough of West View, in the county of Allegheny and State of Pennsylvania,

have invented a new and useful Trip Jack, of which the following is a specification.

The'object of the invention'is to provide an economical and efficient trip ack mechanism and particularly to provide novel and advantageous means and organization whereby the jack can be tripped with slight effort and with security against re-engagement.

In the accompanying drawings, forming a part hereof:

r Fig. 1 is a side elevation of the jack with the operating lever socket raised, the parts being shown in full lines in engagement with the rack and broken lines being used to show how the lifting pawl may be tilted rearward away from the rack preparatory to tripping; r

Fig. 2 is an enlarged fragmentary sectional elevation, the plane of the section being substantially central of the pawl mechanism, which is shown in the tripped condition;

Fig. 3 is a sectional rear elevation of Fig, 2, the section being taken in the vertical axial plane of the main bearing pin, which is seen in elevation;

Fig. 4 is a perspective view of the trip; and I Fig. 5 is'a perspective view of the holding pawl.

The jack has a frame 1, with a toothed rack-bar 2 slidable therein and provided at the top with a jacking head 3 and at the bottom with a foot-step 4. Pivoted in tli erear upper portion of the frame on a main bearing pin 5' is the rocker socket 6 of an operating lever. As seen more particularly in Fig. 3'the end portions of the pin are received in openings in bosses 7 of the frame, and bushings 8 are interposed between these end portions and the frame, the bushings projecting a short distance into the interiorspace of the frame. The rocker is supported on the central portion of the pin between the 50 bushings. the inwardly projecting portions of which are encircled by the openings of the limbs 9 of a bifurcated holding pawl 10.

- Pivoting the holding pawl on the main axis PITTSBURGI L' PENNSYLVANIA, A CORPORATION TRIP JACKL" 1922.- Serial No. 560,351;

affords the most advantageous angular relatron betwe'en'the pawl and rack for purpose of 'trlpping, and the coaxial pivot. supportshavc been devised as described in order to distribute the stresses and brace the pin.

A lifting pawl 11-is pivoted in a notch in the forward upper portion of the lever rocker; and is adaptedto be tilted backward away from the rack through the opening of the holding -pawl. reaching in with-the finger or with a hook, or otherwise. v i V Pivoted on a transverse pin 12' in the frame above the pawlsis' a trip 13, this trip having a downturned nose 14 adapted to press rearward against the front of the upper portion of the holding pawl, and a de pending tail 15 formed with a notched extremity 16 adapted to receive'and be acted upon by the tip of the lifting pawl when the latter is tilted back past the vertical. r

lifting pawl is caused'to work against the tail, swinging the trip slightly rearwardand nosing the holding pawlclear of the rack, 'which is then free to drop. 'Because of the shortness of the nose compared with the length of the tail, and the angular relations the displacement of the holding pawl under load is effected very easily.

When the pawls are disengaged from the rack as shown in Fig. 2, the mechanism locks itself by virtue of the engagement of the tip of the lifting pawl with the tail of the trip arm 13 and the rearwardly-bent toggle relation between these parts. which necessitates raising of'the operating lever before the pawls. or either of them, can reengage with the. rack This insures that while the rack is dropping the pawls can not'rebound into engagementwith the rack teeth, with destructive effect. When the operating lever is raised from the position of comprising twolaterally spaced, duplicate portions; which straddle the beak 17 of the holding pawl to work, upon forwardly fac- This can'be done by rack.

:the lever; and a holding pawl, in combina-- "tron with a trip pivoted on the frame above the Qpawls having a downturned nose adapted to act upon the front of the upper portion of the holding pawland'a depend ing tail to be engaged by the lifting pawl when the latter is tilted'back away from the are a trip jack, the combination of a frame, a rack, an operating lever fulcrumed 1n the frame, a bifurcated holding pawl.

"pivoted on the fulcrum of the operating lever al-ifting pawl pivoted on the aperating' lever and tiltable rearward through the opening of the holding pawl; and a trip pivoted'on the frame above the pawls' and havinga downturned nose adapted to act upon the front of the upper portion of the holding pawl and a depending tail to be engaged by the lifting pawl when the latter-is tilted baolraway from the rack.

3. In a trip jack, a frame, a rack, an oper ating lover, a lifting pawl operated by the;

lever, and a holding pawl, in combination with a trip pivoted on "the frame above the p'awls having a downturned nose adapted to act upon the frontof the upper portion of the holding pawl and a depending tail havinga -notched extremity for engagement by the; lifting pawl when the latter is'tilted back away from the rack.

45111 a trip ack having a frame, a rack,

"and an operating lever,'a lifting pawl operated by the lever. a holding pawl having shoulders at opposite sides of its beak, and, a trip pivoted on the frame above the pawls and having a duplex nose adapted to act' with balanced thrust upon said shouldersand a depending tail to be engaged by the lifting-pawl when the latter is tiltedback away fromthe rack.

5. Ina: trip jack having a frame and a rack, a main bearing pin supported at its ends in the frame, inwardly projecting busl1-- ings' interposed between the end portions ofthe pin and the frame, an operating lever -''on the central portion of said pin,-a bifurcated holding pawl having its limbs on the inner end portions of the-bushings, a

lifting pawl pivoted on the lever and movabl'e backward through the opening of the holding pawl' -and a trip pivoted on. the' act upon the holding pawl and a tail to beacted upon by the lifting paw-l. V

6. In a trip jack having a frame and a rack, the frame having main bearing openings, inwardly porjecting bushingsin said openmgs, a main bearing supportedin said bushings, an operating lever supported on the central portion ofsai'dpi'n between the bushings and carrying a lifting pawl, and. a bifurcated holding pawl having its limbs supported on the inner end portions of said bushings. r

7. In a trip jack, the combination of an operating lever, a lifting pawl, a. holding pawl, and-a trip pivoted on the jack frame above the pawls and having a nose to act" upon the holding pawl and a: tail to be acted upon by the liftingpawl; V

linlatrip jack, the combination of an operating lever, alifting pawl,- a holding pawl, and a trip pivotedon the jack frame above the pawls, said trip having a tail to be acted upon by the lifting pawl-and a nose comprising laterally spaced portions straddling the beak of the holding pawl.

9. In a trip jack having a frame and a rack, the'combinationof an operating lever,

a lifting pawl, a holding pawl, and a trip lever-on the frame constitutin a separate intermediate element adapted to beactuated through the lifting pawl when the latter has been tilted back to throw out. the holding pawl.

1-0. In a: trip jaclna frame, a bifurcated holding pawl, a main bearing pin, anoperat ing lever fulcrumed on. the centralportion frame above the pawls having a nose to of said pin and carrying a lifting pawl,

and inwardly projectin bushings in opposite sides of the frame together supporting said pin and affording trunnions whereon the holding pawliis supported independ ontly of the pin. I 7

:11. In. a trip j aclg-having a rack, an operating lever, a lifting pawl pivoted thereon,

a holding pawl, and trip arm depending from the frame above the lever and lifting pawl and adapted to be engaged by the liftin; pawl when the same is tilted back and the lever "is then; depressed, whereby the holding pawl is disengaged from the rack nd the partslock themselves after the man-z nor of a toggle as long as the lever remains down. V g

12. In a trip jack, having rack, an operating lever, a lifting pawl pivoted thereon, a holding pawl, and a trip arm depending from the frame above the lever and lifti pawl and having a notched end adapted to be engaged. by the lifting pawl when the same is tiltedbaclrand the lever is then depressed, wherebythe holding pawl is disengaged from the rack and the parts lock themselves after the manner of a toggle asllong as the,, lever remains down.

1 end in the frame and normally tilted for- Ward against the rack, and a trip-lever separate from the paWls fulcrumed on the frame above the lever and lifting pawl and arranged to act rearwardly upon the hold-.

ing pawl, the trip lever having a depending arm or tail adapted to be engaged when 10 the lifting pawl is tilted back and the lever is then depressed, whereby the holdingpawl is disengaged from the rack and the parts lock themselves as long as the'lever remains down.

FRANK H. SOHWERIN. 

